Vitamin D Supplements: Over-the-Counter Accessibility... It Is Safe?

Calcium is the fifth most abundant element in earth and human body. It has multiple functions within our system such bone mineralization, neuromuscular excitability regulation, hemostasis, membrane transport, release of hormones and neurotransmitters, among others. For duodenal absorption of calcium, we need vitamin D, reason for which supplementation of both components is important to maintain adequate calcium homeostasis. However, it is entirely beneficial or can be harmful? As we know everything in excess has its consequences, as we describe below. 72 y/o male is brought to the ED after relative find him lethargic, she reports noticing generalized weakness that has been progressing over weeks, prominent in upper extremities with associated increased in urinary frequency. Patient past medical history is relevant for CAD, hypothyroidism, dyslipidemia, and DMT2. On physical examination patient is found hypoactive, but arousable to verbal stimuli, without distress, focal neurologic deficit, thyromegaly nor lymphadenopathy. Presents with Ca+: 18.8mg/dL (n:8.0–10.5mg/dL), that could explain patient clinical presentation for which workup for hypercalcemia is done finding PTH suppress: 14.57pg/mL (n:15-65pg/mL). Patient now with non-PTH related hypercalcemia is further evaluated and found with negative UPEP and SPEP ruling out multiple myeloma and PTH-rp <2.0pmol/L (negative). While etiology of severe hypercalcemia is being study, patient complications of it are being managed such as AKI stage 3 as he presents with Cr: 3.85mg/dL, BUN: 62.5, CrCl:18ml/min and GFR: 15ml/min. Aggressive IV hydration and bisphosphonate therapy failed to decrease calcium and renal function continues worsens, for which hemodialysis is required for calcium clearance. Patient then found with vitamin D25-OH levels: 210.4ng/mL (n:30-100ng/mL), upon questioning he reports taking multivitamins and supplements equivalent for a daily ingestion of 50,700IU of Vitamin D3 and 334mg of calcium carbonate. Patient calcium levels normalize after dialysis but develops renal failure for which he has to be discharged on permanent hemodialysis. Although prevalence is unknown, hypercalcemia due to vitamin D intoxication is relatively uncommon in comparison to hyperparathyroidism and malignancy. An exact dose intake that leads to intoxication has not yet being stablished but supplementation besides dosage is also dependent on duration of therapy. This case has a lot to teach us, starting with detrimental effects of hypercalcemia, follow by the consequences of lack of counseling and close follow-up of patient over-the-counter supplementation. As physicians we should inquire more about OTC medications and supplements our patients are taking not only for intoxication concerns, but also for drugs interactions. Counseling must be the cornerstone of our practice to avoid life changing consequences as in this case.